1. Technical Field
The present disclosure relates to the electronics field, and more particularly to an electronic device having two power transistors in series within a single power device.
2. Description of the Related Art
Each electronic device typically comprises a chip, for example of semiconductor material, on which one or more electronic components are integrated, and a package wherein the chip is embedded for protecting it and for allowing access to its terminals.
In this regard, the package typically comprises an insulating body having exposed leads, each one of which is electrically connected to a corresponding terminal of the chip (for example, by a wire connection technique or “wire-bonding”). The leads of the package are used for connecting it (and hence the corresponding terminals of the chip) to external circuits. For such purpose, the electronic device is typically mounted on a printed circuit board (PCB) comprising such external circuits. In a typical implementation, based on through-hole technology (or THT), the leads of the package comprise reophores or pins adapted to be inserted into through-holes of the PCB and back-welded on it.
A very widespread class of electronic devices is represented by electronic devices for power applications (e.g., for motors control and power supplies) or power devices, which are able of withstanding high operative currents and/or voltages—for example, of the order of 0.3-300 A and 12-1,500V, respectively.
As it is known, the power devices are subject to considerable heating during their operation. For this reason, they are typically designed and used to ensure adequate heat dissipation properties (so as to avoid overheating phenomena to the corresponding chips that might cause malfunction or breakage). In this regard, each through-hole power device is equipped with a heat-sink connected to the chip for dissipating the heat generated during its operation outwards. For this reason, the heat-sink typically comprises a plate exposed on a side surface of the insulating body free from the leads. Furthermore, in use, such a power device is typically fixed to an outer plate of conductive material (also mounted on the PCB) in contact with the exposed plate (in this way, such plate acts both as a supporting member for the power device and as an external heat-sink). For this purpose, the power device is usually provided with a through-hole for its fixing to the outer plate (for example, by screw or bolt).
As it is known, the power devices are widely used in switching circuits, for example for converting a direct voltage into an alternate voltage. For example, a typical switching circuit, referred to as full-bridge switching circuit, comprises two pairs of power electronic switches (e.g., implemented by vertical structure MOS power transistors) in half-bridge configuration for driving a load differentially; in particular, the power transistors of each pair are arranged in series, i.e., they are connected between a reference terminal, or ground, and a supply terminal (with a common terminal that usually defines a corresponding output terminal), whereas the two pairs of power transistors are arranged in parallel between each other (i.e., they share the ground and supply terminals), with the load connected between the respective output terminals.
The power transistors are typically integrated on separate chips (for both technical and economic reasons), with each chip that is typically embedded within a respective package (thus obtaining the corresponding power device). Therefore, in order to obtain a switching circuit, replicated structures of same power devices (e.g., four in case of full-bridge switching circuit) can be separately mounted on the PCB, and suitably connected to each other according to the desired configuration.
However, the switching circuits of this kind are not satisfactory in terms of area occupation, of constructive complexity and heat dissipation efficiency.